Book review: Little Blue Dot

The first time I recall using a map was in boy scouts. Travel in unfamiliar places on foot, bike or car required maps for me for decades. The first time I saw GPS in action was when my brother and I were on Ride the Rockies. We were invited to dinner by a friend in Aspen. After being dropped off in town by a bus, he navigated to our host’s condo with his GPS. A couple years later, I borrowed an old car of his to drive across Colorado for a meeting. The speedometer on the car was broken, so he clamped a GPS receiver to the dashboard that gave a read-out of the speed.

Now, any trip I take out of town requires Siri. It has become essential for us as newcomers in New England. I barely recall what it was like before GPS.

Little Blue Dot, by Katherine Dunn, is a history of GPS. It begins in England during the Blitz, when the Royal Air Force figured out how German bombers were using ratio signals to guide Luftwaffe aircraft for nighttime bombing raids. This led to efforts to jam or spoof those signals, with some success. From this primitive use of electromagnetic signals grew a military program to develop precise guidance systems. This was transformed by Sputnik, leading eventually to a global system of navigation. The military and civilian GPS systems have since become co-mingled. For a while, the civilian GPS was deliberately imprecise in order to discourage enemy military use, but that has since been discontinued.

One thing I hadn’t appreciated before reading this book is the central role of time in the precision of GPS. With atomic clocks, clock time has been accurate within nanoseconds, which allows sufficient precision to guide ships docking and measure global warming-driven sea level change. 

A good part of the last section is taken up with the issue of jamming and spoofing GPS, which has been going on for years in places of conflict and along the Russian border and which has gotten to be very cheap and mobile. A related issue is solar flares that could inactivate a bunch of GPS satellites. I was disturbed enough thinking about this that I downloaded pdf maps of our route for our upcoming vacation to my laptop as a back-up.

The writing here is lively and engrossing. I’ll confess that I didn’t follow some of the technical language, but the book is intended for a lay audience and for the most part I think it met that challenge. I recommend it.